The 1860 Republican Party convention in Chicago created a platform that clearly opposed the expansion of slavery in the West and the reopening of the slave trade. However, nothing in the document claimed that the government had the power to eliminate slavery where it already existed. Controversies over slavery suffuse the platform, but maybe even more noticeable is the importance of the West to the Republican Party.  

Resolved, That we, the delegated representatives of the Republican electors of the United States in Convention assembled, in discharge of the duty we owe to our constituents and our country, unite in the following declarations:

1. That the history of the nation during the last four years, has fully established the propriety and necessity of the organization and perpetuation of the Republican party, and that the causes which called it into existence are permanent in their nature, and now, more than ever before, demand its peaceful and constitutional triumph.
2. That the maintenance of the principles promulgated in the Declaration of Independence and embodied in the Federal Constitution, “That all men are created equal; that they are endowed by their Creator with certain inalienable rights; that among these are life, liberty and the pursuit of happiness; that to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed,” is essential to the preservation of our Republican institutions; and that the Federal Constitution, the Rights of the States, and the Union of the States must and shall be preserved.
3. That to the Union of the States this nation owes its unprecedented increase in population, its surprising development of material resources, its rapid augmentation of wealth, its happiness at home and its honor abroad; and we hold in abhorrence all schemes for disunion, come from whatever source they may. And we congratulate the country that no Republican member of Congress has uttered or countenanced the threats of disunion so often made by Democratic members, without rebuke and with applause from their political associates; and we denounce those threats of disunion, in case of a popular overthrow of their ascendency as denying the vital principles of a free government, and as an avowal of contemplated treason, which it is the imperative duty of an indignant people sternly to rebuke and forever silence.
4. That the maintenance inviolate of the rights of the states, and especially the right of each state to order and control its own domestic institutions according to its own judgment exclusively, is essential to that balance of powers on which the perfection and endurance of our political fabric depends; and we denounce the lawless invasion by armed force of the soil of any state or territory, no matter under what pretext, as among the gravest of crimes.
5. That the present Democratic Administration has far exceeded our worst apprehensions, in its measureless subserviency to the exactions of a sectional interest, as especially evinced in its desperate exertions to force the infamous Lecompton Constitution upon the protesting people of Kansas; in construing the personal relations between master and servant to involve an unqualified property in persons; in its attempted enforcement everywhere, on land and sea, through the intervention of Congress and of the Federal Courts of the extreme pretensions of a purely local interest; and in its general and unvarying abuse of the power intrusted to it by a confiding people.
6. That the people justly view with alarm the reckless extravagance which pervades every department of the Federal Government; that a return to rigid economy and accountability is indispensable to arrest the systematic plunder of the public treasury by favored partisans; while the recent startling developments of frauds and corruptions at the Federal metropolis, show that an entire change of administration is imperatively demanded.
7. That the new dogma that the Constitution, of its own force, carries slavery into any or all of the territories of the United States, is a dangerous political heresy, at variance with the explicit provisions of that instrument itself, with contemporaneous exposition, and with legislative and judicial precedent; is revolutionary in its tendency, and subversive of the peace and harmony of the country.
8. That the normal condition of all the territory of the United States is that of freedom: That, as our Republican fathers, when they had abolished slavery in all our national territory, ordained that “no persons should be deprived of life, liberty or property without due process of law,” it becomes our duty, by legislation, whenever such legislation is necessary, to maintain this provision of the Constitution against all attempts to violate it; and we deny the authority of Congress, of a territorial legislature, or of any individuals, to givelegal existence to slavery in any territory of the United States.
9. That we brand the recent reopening of the African slave trade, under the cover of our national flag, aided by perversions of judicial power, as a crime against humanity and a burning shame to our country and age; and we call upon Congress to take prompt and efficient measures for the total and final suppression of that execrable traffic
10. That in the recent vetoes, by their Federal Governors, of the acts of the legislatures of Kansas and Nebraska, prohibiting slavery in those territories, we find a practical illustration of the boasted Democratic principle of Non-Intervention and Popular Sovereignty, embodied in the Kansas-Nebraska Bill, and a demonstration of the deception and fraud involved therein.
11. That Kansas should, of right, be immediately admitted as a state under the Constitution recently formed and adopted by her people, and accepted by the House of Representatives.
12. That, while providing revenue for the support of the general government by duties upon imports, sound policy requires such an adjustment of these imports as to encourage the development of the industrial interests of the whole country; and we commend that policy of national exchanges, which secures to the workingmen liberal wages, to agriculture remunerative prices, to mechanics and manufacturers an adequate reward for their skill, labor, and enterprise, and to the nation commercial prosperity and independence.
13. That we protest against any sale or alienation to others of the public lands held by actual settlers, and against any view of the free-homestead policy which regards the settlers as paupers or suppliants for public bounty; and we demand the passage by Congress of the complete and satisfactory homestead measure which has already passed the House.
14. That the Republican party is opposed to any change in our naturalization laws or any state legislation by which the rights of citizens hitherto accorded to immigrants from foreign lands shall be abridged or impaired; and in favor of giving a full and efficient protection to the rights of all classes of citizens, whether native or naturalized, both at home and abroad.
15. That appropriations by Congress for river and harbor improvements of a national character, required for the accommodation and security of an existing commerce, are authorized by the Constitution, and justified by the obligation of Government to protect the lives and property of its citizens.
16. That a railroad to the Pacific Ocean is imperatively demanded by the interests of the whole country; that the federal government ought to render immediate and efficient aid in its construction; and that, as preliminary thereto, a daily overland mail should be promptly established.

Republican Party Platforms: “Republican Party Platform of 1860,” May 17, 1860. Online by Gerhard Peters and John T. Woolley, The American Presidency Project.

Available through the University of California at Santa Barbara